Facile one-pot synthesis of novel dicyanoanilines fused to tetrahydro-4 H -thiopyran-4-one ring via Et 3 N/H 2 O catalyzed pseudo four-component reaction

Tetrahydro-4H-thiopyran-4-one, 1 , undergoes a pseudo four-component reaction with various aldehydes bearing different groups and two equivalents of malononitrile in aqueous media in the presence of triethylamine (Et 3 N). As a result, novel thiopyran-fused dicyanoanilines 4 are formed efficiently in the reaction mixtures in 90–97% yield within 9–12 h mixing at 40°C. Due to the polarity of the medium, products precipitate in the mixture spontaneously allowing for easy purification by recrystallization avoiding cumbersome chromatographic separations.

Characterization of the products was performed by spectroscopic methods and, in one case, was further supported by X-ray crystallographic experiments.